Cyclic ketones are oxidized to lactones or hydroxy acids with peracids in the Baeyer-Villinger reaction and such peracids include persulfuric, perbenzoic, perphthalic, peracetic and trifluoroperacetic acid. In some instances peracids can be substituted by concentrated (90%) H.sub.2 O.sub.2 and carboxylic acid anhydride.
S. Kamimura in Japan Pat. No. 2728/1970 dated Jan. 29, 1970 discloses a method for making 6-hydroxycaproic acid or its derivative by decomposition of cyclohexanone peroxides in the presence of arsenic catalysts.
S. Kamimura in Japan Pat. No. 10243-1969 issued May 13, 1969 discloses a method for making esters by oxidation of ketones with hydrogen peroxide in the presence of organic and inorganic arsenic compounds. Employing H.sub.2 O.sub.2 as the oxidant, this reference gives 6-hydroxycaproic acid as the main product. In the presence of secondary alcohols such as cyclohexanol the lactone was solvolysed to the corresponding alkyl 6-hydroxy caproate resulting in a low yield of lactone.